Definition

The indicator Healthy life years (HLY) is defined as the expected number of remaining years free of health impairments (EHLEIS, 2019, Bogaert et al., 2018) of people with diabetes compared to people without diabetes.

Operationalisation

The calculation of the indicator requires various figures that are used to estimate the number of healthy life years a person would have lived for:

• Prevalence of known diabetes: participant’s response to the question: ‘Have you ever been diagnosed with diabetes by a doctor?’

• Prevalence of health limitations:

  • Participant’s response to the question: ‘To what extent are you permanently limited in your everyday activities due to illness? By permanent we mean for at least half a year.’

    • Severely limited
    • Limited but not severely
    • Not limited
    • I do not know
    • No reply
  • Prevalence: The proportion of people who stated ‘severely limited’. Complementary groups are people who stated ‘limited but not severely’ or ‘not limited’.

• Death rate in the general population: The death rates are determined using the cause of death statistics of the Federal Statistical Office.

• Diabetes-related excess mortality: The ratio of the death rate for people with documented diabetes to the death rate for people without documented diabetes (see Mortality indicator).

• The specified figures are reported in total and separately for sex for people from 30 to 89 years in 10-year age groups; people aged 90 years and over are combined into one age group.

Reference population

Resident population in Germany, aged 30 years and over

Data source

Three data sources are used to measure the various indicators:

• The prevalences of diabetes and health impairments are based on three RKI interview surveys (GEDA 2009, GEDA 2010, GEDA 2012) based on telephone samples (landline) and telephone-based questionnaire.
• The mortality rates are based on 2014 data from the Federal Statistical Office.
• The figures on diabetes-related excess mortality are based on DaTraV data from 2014 (see Mortality indicator)

Calculation

The number of healthy life years is determined in three steps:

• Diabetes-specific death rates: In the first step, mortality rates for people with diabetes and for people without diabetes are determined using the mortality rate in the general population, diabetes prevalence and diabetes-related excess mortality.
• Life expectancy: In the second step, the life expectancy for people with and without diabetes is determined using the diabetes-specific death rates.
• Healthy life years: In the third step, the number of remaining healthy years of life is determined using the age-specific life expectancy and the age-specific prevalence of health limitations using the Sullivan method.
• Weighting: Weighting factors are used to calculate the prevalence of diabetes and health complaints, which correct for selection bias as well as deviations in the sample from the population structure based on 31 December 2011 with regard to sex, age, education and regional distribution.

Data quality

• RKI interview surveys provide representative results for the resident population of Germany aged 18 years and over. As is the case in all population-based studies, underrepresentation of the seriously ill and those living in institutions must be assumed. Furthermore, all information is self-reported and not based on personal interviews conducted by study physicians or standardized measurements or examinations.
• Mortality rates for Germany are drawn from the offi­cial statistics of the Federal Statistical Office. When determining life expectancy, the current mortality ratios are used and thus assumed to be constant over time, which can lead to an underestimation of actual life expectancy.
• DaTraV data are claims data on all people covered by SHI. DaTraV data include documented outpatient and inpatient diagnoses as well as information on prescribed medications. The quality of claims data from SHI depends on conduct of documentation. DaTraV data do not cover people insured by private health insurance and do not provide information on inpatient or outpatient care.